A wide variety of cultivating tools have evolved over the years for the tillage of soil. Such tools have been designed for a variety of purposes and soil conditions. Wing sweeps evolved for the purpose of performing the function of cutting off or uprooting weeds as well as for breaking up or mulching the surface of the soil in order to conserve soil moisture.
Wing sweep designs generally include a forwardly pointed body which is attached to a cultivating implement of some sort. Such wing sweeps include a pair of blades or wings which extend rearwardly from opposite sides of the body, or in some cases, a single blade or wing on one side of the body only. The body wings have customarily been provided with cutting edges extending rearwardly from the point of the body and along the outer front edges of the wings, the wings and the body being shaped so that the cutting edges are in the pattern of a "V" with the apex of the "V" being at the point. In many types of such sweeps, the V-pattern edge lies substantially in a plane. In the transverse direction, the wing or blade inclines upwardly and outwardly from the edge.
Such sweeps are adapted for use on cultivator implements that are drawn by tractors whereby they are propelled at a high forward velocity through the soil and subjected to substantial mechanical strains. Examples of wing sweep designs are disclosed in U.S. Pat. Nos. 5,176,209, 4,787,462 2,351,388, 2,595,353, 2,704,499 and 3,038,424, incorporated herein by reference. As can be seen from these particular prior art patents, the V-shaped wing sweep design as described above is common. The basis for this V-shape design resides in the modern approach to sweep cultivation wherein evaporation of moisture from soil can be reduced if a layer of the surface soil is sliced or sheared off from the underlying soil and then replaced with a minimum of soil agitation with the soil surface being left relatively level without furrows and ridges. The sweep designs of the above-referenced patents contribute to this concept of cultivation and mulching in various ways and include wings that diverge rearwardly in a "V" so that the soil flows rearwardly over the body of the sweep and falls by gravity downwardly between the stern and wings and is not thrown or plowed violently toward the sides. The soil is thus replaced on the ground surface between the wings rearwardly of the sweep and avoids the plowing of the sweep wing portions. It will be appreciated that in the V-shape designs, the nose or tip of the sweep tends to flatten to a very blunt shape. When this occurs drawing of the sweep through the soil can become very difficult since the tip is not sufficiently sharp to cause easy initial separation of the soil and penetration of the sweep through the soil. Another wear characteristic of the existing sweep designs is that such sweeps also tend to wear faster at the distal tip portions of the wings as opposed to the center of the wings. This wearing of the end portions of the wings tends to reduce the width of the sweep during its lifetime, thus narrowing the path which the sweep makes through the soil. Since the purpose of the sweep is to shear as much surface soil as possible at one time, this narrowing of the sweep reduces the effectiveness and efficiency of the cultivating tool carrying the sweep or a plurality of such sweeps.
Finally, sweeps have incorporated a cutting edge inclined to the surface of the ground in order to increase the penetration and cutting capability of the sweep. In order to increase the angle of inclination to the ground, the rear portions of the wing members have generally been designed to be uplifted relative to the ground surface as in U.S. Pat. Nos. 2,351,388 and 2,704,499, incorporated herein by reference. A problem with such uplifting of the rear portion of the sweep is that it will achieve better penetration into the ground, the elevation of the rear portion of the sweep will tend to increase the agitation of the soil.
The cultivator sweeps such as disclosed in U.S. Pat. No. 4,787,462 include a stem designed to attach the cultivator sweep to a support member of a cultivating implement. The stem attaches over a vertical shank of a standard cultivating implement. A problem with such attachment is that the cultivator sweep is mechanically fastened to the vertical shank and can come loose and fall off the vertical shank. Furthermore, the mechanical fastener must be either loosened and/or tightened to remove and/or attach the cultivator sweep to the vertical shank thereby increasing downtime of the cultivating implement.
Although the various cultivator sweep assembly designs have been proven to perform satisfactorily, further improvements on the design of cultivator sweeps is desired. An object of the present invention is to provide a cultivator sweep assembly including a cultivator sweep and sweep holder that is simple to attach and economical to make. Yet another object of the present invention is to provide a cultivator sweep assembly that is secured to a sweep holder by an interference fit. Still another object of the present invention is to provide a cultivator sweep assembly that is secured to a sweep holder and is retained against the sweep holder by the action of the cultivator sweep passing through the soil.